// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stddef.h>

#include <algorithm>

#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/string_piece.h"
#include "base/strings/utf_offset_string_conversions.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

namespace {

    static const size_t kNpos = string16::npos;

} // namespace

TEST(UTFOffsetStringConversionsTest, AdjustOffset)
{
    struct UTF8ToUTF16Case {
        const char* utf8;
        size_t input_offset;
        size_t output_offset;
    } utf8_to_utf16_cases[] = {
        { "", 0, 0 },
        { "", kNpos, kNpos },
        { "\xe4\xbd\xa0\xe5\xa5\xbd", 1, kNpos },
        { "\xe4\xbd\xa0\xe5\xa5\xbd", 3, 1 },
        { "\xed\xb0\x80z", 3, 1 },
        { "A\xF0\x90\x8C\x80z", 1, 1 },
        { "A\xF0\x90\x8C\x80z", 2, kNpos },
        { "A\xF0\x90\x8C\x80z", 5, 3 },
        { "A\xF0\x90\x8C\x80z", 6, 4 },
        { "A\xF0\x90\x8C\x80z", kNpos, kNpos },
    };
    for (size_t i = 0; i < arraysize(utf8_to_utf16_cases); ++i) {
        const size_t offset = utf8_to_utf16_cases[i].input_offset;
        std::vector<size_t> offsets;
        offsets.push_back(offset);
        UTF8ToUTF16AndAdjustOffsets(utf8_to_utf16_cases[i].utf8, &offsets);
        EXPECT_EQ(utf8_to_utf16_cases[i].output_offset, offsets[0]);
    }

    struct UTF16ToUTF8Case {
        char16 utf16[10];
        size_t input_offset;
        size_t output_offset;
    } utf16_to_utf8_cases[] = {
        { {}, 0, 0 },
        // Converted to 3-byte utf-8 sequences
        { { 0x5909, 0x63DB }, 3, kNpos },
        { { 0x5909, 0x63DB }, 2, 6 },
        { { 0x5909, 0x63DB }, 1, 3 },
        { { 0x5909, 0x63DB }, 0, 0 },
        // Converted to 2-byte utf-8 sequences
        { { 'A', 0x00bc, 0x00be, 'z' }, 1, 1 },
        { { 'A', 0x00bc, 0x00be, 'z' }, 2, 3 },
        { { 'A', 0x00bc, 0x00be, 'z' }, 3, 5 },
        { { 'A', 0x00bc, 0x00be, 'z' }, 4, 6 },
        // Surrogate pair
        { { 'A', 0xd800, 0xdf00, 'z' }, 1, 1 },
        { { 'A', 0xd800, 0xdf00, 'z' }, 2, kNpos },
        { { 'A', 0xd800, 0xdf00, 'z' }, 3, 5 },
        { { 'A', 0xd800, 0xdf00, 'z' }, 4, 6 },
    };
    for (size_t i = 0; i < arraysize(utf16_to_utf8_cases); ++i) {
        size_t offset = utf16_to_utf8_cases[i].input_offset;
        std::vector<size_t> offsets;
        offsets.push_back(offset);
        UTF16ToUTF8AndAdjustOffsets(utf16_to_utf8_cases[i].utf16, &offsets);
        EXPECT_EQ(utf16_to_utf8_cases[i].output_offset, offsets[0]) << i;
    }
}

TEST(UTFOffsetStringConversionsTest, LimitOffsets)
{
    const size_t kLimit = 10;
    const size_t kItems = 20;
    std::vector<size_t> size_ts;
    for (size_t t = 0; t < kItems; ++t)
        size_ts.push_back(t);
    std::for_each(size_ts.begin(), size_ts.end(),
        LimitOffset<string16>(kLimit));
    size_t unlimited_count = 0;
    for (std::vector<size_t>::iterator ti = size_ts.begin(); ti != size_ts.end();
         ++ti) {
        if (*ti != kNpos)
            ++unlimited_count;
    }
    EXPECT_EQ(11U, unlimited_count);

    // Reverse the values in the vector and try again.
    size_ts.clear();
    for (size_t t = kItems; t > 0; --t)
        size_ts.push_back(t - 1);
    std::for_each(size_ts.begin(), size_ts.end(),
        LimitOffset<string16>(kLimit));
    unlimited_count = 0;
    for (std::vector<size_t>::iterator ti = size_ts.begin(); ti != size_ts.end();
         ++ti) {
        if (*ti != kNpos)
            ++unlimited_count;
    }
    EXPECT_EQ(11U, unlimited_count);
}

TEST(UTFOffsetStringConversionsTest, AdjustOffsets)
{
    // Imagine we have strings as shown in the following cases where the
    // X's represent encoded characters.
    // 1: abcXXXdef ==> abcXdef
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 9; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(3, 3, 1));
        OffsetAdjuster::AdjustOffsets(adjustments, &offsets);
        size_t expected_1[] = { 0, 1, 2, 3, kNpos, kNpos, 4, 5, 6, 7 };
        EXPECT_EQ(offsets.size(), arraysize(expected_1));
        for (size_t i = 0; i < arraysize(expected_1); ++i)
            EXPECT_EQ(expected_1[i], offsets[i]);
    }

    // 2: XXXaXXXXbcXXXXXXXdefXXX ==> XaXXbcXXXXdefX
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 23; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(0, 3, 1));
        adjustments.push_back(OffsetAdjuster::Adjustment(4, 4, 2));
        adjustments.push_back(OffsetAdjuster::Adjustment(10, 7, 4));
        adjustments.push_back(OffsetAdjuster::Adjustment(20, 3, 1));
        OffsetAdjuster::AdjustOffsets(adjustments, &offsets);
        size_t expected_2[] = {
            0, kNpos, kNpos, 1, 2, kNpos, kNpos, kNpos, 4, 5, 6, kNpos, kNpos, kNpos,
            kNpos, kNpos, kNpos, 10, 11, 12, 13, kNpos, kNpos, 14
        };
        EXPECT_EQ(offsets.size(), arraysize(expected_2));
        for (size_t i = 0; i < arraysize(expected_2); ++i)
            EXPECT_EQ(expected_2[i], offsets[i]);
    }

    // 3: XXXaXXXXbcdXXXeXX ==> aXXXXbcdXXXe
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 17; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(0, 3, 0));
        adjustments.push_back(OffsetAdjuster::Adjustment(4, 4, 4));
        adjustments.push_back(OffsetAdjuster::Adjustment(11, 3, 3));
        adjustments.push_back(OffsetAdjuster::Adjustment(15, 2, 0));
        OffsetAdjuster::AdjustOffsets(adjustments, &offsets);
        size_t expected_3[] = {
            0, kNpos, kNpos, 0, 1, kNpos, kNpos, kNpos, 5, 6, 7, 8, kNpos, kNpos, 11,
            12, kNpos, 12
        };
        EXPECT_EQ(offsets.size(), arraysize(expected_3));
        for (size_t i = 0; i < arraysize(expected_3); ++i)
            EXPECT_EQ(expected_3[i], offsets[i]);
    }
}

TEST(UTFOffsetStringConversionsTest, UnadjustOffsets)
{
    // Imagine we have strings as shown in the following cases where the
    // X's represent encoded characters.
    // 1: abcXXXdef ==> abcXdef
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 7; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(3, 3, 1));
        OffsetAdjuster::UnadjustOffsets(adjustments, &offsets);
        size_t expected_1[] = { 0, 1, 2, 3, 6, 7, 8, 9 };
        EXPECT_EQ(offsets.size(), arraysize(expected_1));
        for (size_t i = 0; i < arraysize(expected_1); ++i)
            EXPECT_EQ(expected_1[i], offsets[i]);
    }

    // 2: XXXaXXXXbcXXXXXXXdefXXX ==> XaXXbcXXXXdefX
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 14; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(0, 3, 1));
        adjustments.push_back(OffsetAdjuster::Adjustment(4, 4, 2));
        adjustments.push_back(OffsetAdjuster::Adjustment(10, 7, 4));
        adjustments.push_back(OffsetAdjuster::Adjustment(20, 3, 1));
        OffsetAdjuster::UnadjustOffsets(adjustments, &offsets);
        size_t expected_2[] = {
            0, 3, 4, kNpos, 8, 9, 10, kNpos, kNpos, kNpos, 17, 18, 19, 20, 23
        };
        EXPECT_EQ(offsets.size(), arraysize(expected_2));
        for (size_t i = 0; i < arraysize(expected_2); ++i)
            EXPECT_EQ(expected_2[i], offsets[i]);
    }

    // 3: XXXaXXXXbcdXXXeXX ==> aXXXXbcdXXXe
    {
        std::vector<size_t> offsets;
        for (size_t t = 0; t <= 12; ++t)
            offsets.push_back(t);
        OffsetAdjuster::Adjustments adjustments;
        adjustments.push_back(OffsetAdjuster::Adjustment(0, 3, 0));
        adjustments.push_back(OffsetAdjuster::Adjustment(4, 4, 4));
        adjustments.push_back(OffsetAdjuster::Adjustment(11, 3, 3));
        adjustments.push_back(OffsetAdjuster::Adjustment(15, 2, 0));
        OffsetAdjuster::UnadjustOffsets(adjustments, &offsets);
        size_t expected_3[] = {
            0, // this could just as easily be 3
            4, kNpos, kNpos, kNpos, 8, 9, 10, 11, kNpos, kNpos, 14,
            15 // this could just as easily be 17
        };
        EXPECT_EQ(offsets.size(), arraysize(expected_3));
        for (size_t i = 0; i < arraysize(expected_3); ++i)
            EXPECT_EQ(expected_3[i], offsets[i]);
    }
}

// MergeSequentialAdjustments is used by net/base/escape.{h,cc} and
// net/base/net_util.{h,cc}.  The two tests EscapeTest.AdjustOffset and
// NetUtilTest.FormatUrlWithOffsets test its behavior extensively.  This
// is simply a short, additional test.
TEST(UTFOffsetStringConversionsTest, MergeSequentialAdjustments)
{
    // Pretend the input string is "abcdefghijklmnopqrstuvwxyz".

    // Set up |first_adjustments| to
    // - remove the leading "a"
    // - combine the "bc" into one character (call it ".")
    // - remove the "f"
    // - remove the "tuv"
    // The resulting string should be ".deghijklmnopqrswxyz".
    OffsetAdjuster::Adjustments first_adjustments;
    first_adjustments.push_back(OffsetAdjuster::Adjustment(0, 1, 0));
    first_adjustments.push_back(OffsetAdjuster::Adjustment(1, 2, 1));
    first_adjustments.push_back(OffsetAdjuster::Adjustment(5, 1, 0));
    first_adjustments.push_back(OffsetAdjuster::Adjustment(19, 3, 0));

    // Set up |adjustments_on_adjusted_string| to
    // - combine the "." character that replaced "bc" with "d" into one character
    //   (call it "?")
    // - remove the "egh"
    // - expand the "i" into two characters (call them "12")
    // - combine the "jkl" into one character (call it "@")
    // - expand the "z" into two characters (call it "34")
    // The resulting string should be "?12@mnopqrswxy34".
    OffsetAdjuster::Adjustments adjustments_on_adjusted_string;
    adjustments_on_adjusted_string.push_back(OffsetAdjuster::Adjustment(
        0, 2, 1));
    adjustments_on_adjusted_string.push_back(OffsetAdjuster::Adjustment(
        2, 3, 0));
    adjustments_on_adjusted_string.push_back(OffsetAdjuster::Adjustment(
        5, 1, 2));
    adjustments_on_adjusted_string.push_back(OffsetAdjuster::Adjustment(
        6, 3, 1));
    adjustments_on_adjusted_string.push_back(OffsetAdjuster::Adjustment(
        19, 1, 2));

    // Now merge the adjustments and check the results.
    OffsetAdjuster::MergeSequentialAdjustments(first_adjustments,
        &adjustments_on_adjusted_string);
    // The merged adjustments should look like
    // - combine abcd into "?"
    //   - note: it's also reasonable for the Merge function to instead produce
    //     two adjustments instead of this, one to remove a and another to
    //     combine bcd into "?".  This test verifies the current behavior.
    // - remove efgh
    // - expand i into "12"
    // - combine jkl into "@"
    // - remove tuv
    // - expand z into "34"
    ASSERT_EQ(6u, adjustments_on_adjusted_string.size());
    EXPECT_EQ(0u, adjustments_on_adjusted_string[0].original_offset);
    EXPECT_EQ(4u, adjustments_on_adjusted_string[0].original_length);
    EXPECT_EQ(1u, adjustments_on_adjusted_string[0].output_length);
    EXPECT_EQ(4u, adjustments_on_adjusted_string[1].original_offset);
    EXPECT_EQ(4u, adjustments_on_adjusted_string[1].original_length);
    EXPECT_EQ(0u, adjustments_on_adjusted_string[1].output_length);
    EXPECT_EQ(8u, adjustments_on_adjusted_string[2].original_offset);
    EXPECT_EQ(1u, adjustments_on_adjusted_string[2].original_length);
    EXPECT_EQ(2u, adjustments_on_adjusted_string[2].output_length);
    EXPECT_EQ(9u, adjustments_on_adjusted_string[3].original_offset);
    EXPECT_EQ(3u, adjustments_on_adjusted_string[3].original_length);
    EXPECT_EQ(1u, adjustments_on_adjusted_string[3].output_length);
    EXPECT_EQ(19u, adjustments_on_adjusted_string[4].original_offset);
    EXPECT_EQ(3u, adjustments_on_adjusted_string[4].original_length);
    EXPECT_EQ(0u, adjustments_on_adjusted_string[4].output_length);
    EXPECT_EQ(25u, adjustments_on_adjusted_string[5].original_offset);
    EXPECT_EQ(1u, adjustments_on_adjusted_string[5].original_length);
    EXPECT_EQ(2u, adjustments_on_adjusted_string[5].output_length);
}

} // namespace base
